From ca42f46565d9d2869937ffd7a8bb6e7a4c438b04 Mon Sep 17 00:00:00 2001
From: Sarah Zakarias <zarah@google.com>
Date: Thu, 14 Nov 2024 14:56:29 +0100
Subject: [PATCH] Handle special case in sparkline chart where all values are 0
 (#8287)

---
 pkg/web_app/lib/src/widget/weekly_sparkline/widget.dart | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pkg/web_app/lib/src/widget/weekly_sparkline/widget.dart b/pkg/web_app/lib/src/widget/weekly_sparkline/widget.dart
index 7d2c43680..c63c8b16b 100644
--- a/pkg/web_app/lib/src/widget/weekly_sparkline/widget.dart
+++ b/pkg/web_app/lib/src/widget/weekly_sparkline/widget.dart
@@ -53,7 +53,9 @@ void drawChart(Element svg, HTMLDivElement toolTip, HTMLDivElement chartSubText,
   final firstDay = firstDate.copyWith(day: firstDate.day - 7);
 
   final xAxisSpan = lastDate.difference(firstDate);
-  final maxDownloads = data.fold<int>(0, (a, b) => max<int>(a, b.downloads));
+  // We start with 1 as initial value. In the special case where all downloads
+  // are 0 we want a straight line in the bottom of the chart.
+  final maxDownloads = data.fold<int>(1, (a, b) => max<int>(a, b.downloads));
 
   final toolTipOffsetFromMouse = 15;